QGIS is a user-friendly, cross-platform GIS application licensed under the GNU General Public License.

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3
votes
1answer
79 views

How do I merge DEM rasters correctly?

I've been struggling with this problem for awhile. Here is a curvature raster to illustrate the problem. I'm using 10m DEM rasters from the NRCS Data Gateway for a large portion of California. The ...
1
vote
1answer
21 views

QGIS: OSM Landscape layer not printed

I am new in GIS and I am trying to print a new map. If I use Google Street and web layer, it got printed without problem in the composer, but OSM Landscape does not appear on the printed document (it ...
3
votes
2answers
54 views

Locate points that are within a certain distance of other points in QGIS

I need a way of locating all points in my dataset that are within a certain distance of any other point. For example, in the following data set in which EASTING AND NORTHING are British National Grid ...
2
votes
1answer
31 views

View with sequence in QGIS 2.4

In postgres, I created a view with a sequence nextval() to have an unique id (called vid). I tried to vizualise this view in QGIS but it failed. It seems that nexval() causes some issue according to a ...
3
votes
1answer
58 views

Distincly color world map by language in QGIS 2.4

For a map of Wikipedia language prefixes, I need to color a map by a country's value in the 'language' column. I. e. all countries with the same language worldwide should share a color, which they ...
2
votes
0answers
29 views

How to calculate surface out of GPS points in QGIS

I have uploaded several squares (which consist out of 4 GPS points, not connected). I need the total surface of the squares. Is there a simple way of doing this? Do I create polygons and than ...
-1
votes
0answers
37 views

How to load Google Satellite images in QGIS using python [on hold]

I have to write a python program to remove all the existing vector layers in QGIS. I then have to write a python program to load the Google satellite images. Please help me by answering this ...
0
votes
1answer
31 views

How to manage the CRS of Open-Layers plugin in QGIS?

I am working with OpenLayers plugin in QGIS 1.8 but I am not sure on how should I manage thc CRS. The defaul CRS for Googles/Bing layers is WGS84/Pseudo Mercator (EPGS:3857) but I am not sure on the ...
0
votes
1answer
30 views

How to run and debug PyQGIS scripts in PyCharm Community Edition 3.4.1

I am working with creating plugins for QGIS 2.4.0 (Chugiak). I am curious to know how I can write the codes, and debug them in the environment I am comfortable in, i.e. PyCharm Community Edition ...
1
vote
0answers
19 views

QGIS PointConnector Plugin - x out of x lines not drawn

Unfortunately every try to generate lines between points (.shp) with ids (1-6) and a csv-file with from - to values failed. Maybe you can give me a hint whats wrong with my workflow? 1) I generated a ...
0
votes
2answers
58 views

How to draw a perfect circle with a set radius in meters on map?

Following this istructions on how to draw a circle I can make buffer layer on each point I need. I am not able to draw perfects circle because the buffer will be elliptic? The CSR is EPSG:4326 - WGS ...
0
votes
0answers
29 views

Open a *.qgs project file in API, why maps do not show?

I'm using QGIS-2.4.0 API. I saved a test.qgs file in QGIS Desktop, in this project, there is one layer that is visible in it. Then I open the test.qgs project file in QGIS API to developing an App, ...
4
votes
1answer
72 views

Why are my calls to SAGA routines in QGIS not working cross platform?

The ability to write and run cross platform scripts for QGIS using python is OUTSTANDING! However, when I try to run the SAGA:MERGESHAPESLAYERS algorithm from a python script it works fine in windows ...
7
votes
0answers
94 views

How to produce high-resolution DEMs from new Sentinel-1 data?

This is a general question relating to the new Sentinel-1 data. I'm interested in the potential for using this data to create high resolution DEMs in GIS (I use QGIS), to investigate archaeological ...
3
votes
0answers
48 views

Issue with dissolving a polygons layer in QGIS 2.4

I downloaded a dataset of roads and parks from OSM. I then buffered the roads and merged with the parks. Now - all i want is to dissolve / union all the features in the merged layer. I fail to do it ...
1
vote
1answer
33 views

How to save multiple layers from QGIS to a Spatialite db?

I thought I had asked this before but I can't find any trace of it. Each time I save a layer from QGIS as a spatialite it insists on creating a new db ( if you select a existing db you are asked ...
1
vote
1answer
30 views

QGIS: How to get Symbols saved in GPX Files

I have some waypoint layers that contain different types of points and I distinguish these in QGIS by different symbols and colours. I want to export these to a GPX file that I can download to my GPS ...
2
votes
0answers
23 views

How to move to the next feature in the polygon with user keyboard inputs

I am new to this qgis i have one question. There is one rectangle and it is divided into some 20 grids.I wrote a program to zoom into the each feature.but if i am in one feature i want to move to the ...
1
vote
1answer
40 views

Open Source solution to batch process shortest distance between points along road networks?

I have the locations geocoded (a fairly small dataset, ~200), but I haven't found a straightforward way to load these data into QGIS and perform network analysis between nodes. Any suggestions? ...
1
vote
1answer
28 views

Convert From Northing/Eastings to Latitude/Longitude with QGIS

How can I convert a file with the projection below (NAD83) to one with Latitude and Longitude? The import file is a SHP file and I would like to export back out a SHP file. +proj=tmerc +lat_0=0 ...
2
votes
0answers
24 views

Assigning Color Ramp using PyQGIS

According to the PyQGIS Cookbook, a color ramp can be assigned in the following way: rlayer.setColorShadingAlgorithm(QgsRasterLayer.ColorRampShader) lst = [ QgsColorRampShader.ColorRampItem(0, ...
0
votes
1answer
57 views

Creating Map from database

I'd like some general advice on creating dynamic maps. I have a bunch of geospatial points saved on SQL Server and PostgreSQL. People will enter new data into the databases from time to time. I want ...
1
vote
2answers
42 views

Contour of single feature on QGIS

I'm trying to extract one single contour line at given elevation from a DEM. Taking into account that I want only one contour and not all contours with the given elevation, is there a way to do it in ...
1
vote
1answer
15 views

Print with different settings of layer view?

Using QGIS is it possible to print on the same paper two windows with different settings of layer? I mean: window1: layer1 ON - layer2 OFF window2: layer1 OFF - layer2 ON
2
votes
2answers
49 views

Printing A3 format map

I have a question about printing A3 map from QGIS. I'm going to make A3 map of one country and nearby countries, digitalise borders etc. I want to save it to A3 format, but I have only A4 printer, ...
1
vote
1answer
28 views

How to load territorial maps on QGIS from web?

Is it possible to use QGIS like Google Earth? I need to draw simple shapes on territorial maps. I would like to do that without using multiple files for each part of the Earth. I use QGIS 1.8, but I ...
1
vote
0answers
27 views

Raster calculation with string in modeler

In my model I have one raster file and also a string input (factor for further calculation). I tried to use the grass r.mapcalculator where I can find the raster and also the string input. I tried to ...
1
vote
1answer
19 views

Problem by changing the order of Layers in QGis Layer Tree

I'm using QGis 2.4 on a virtual machine (Ubuntu 14.4 with XFCE). I'm connected to the VM via vncviewer, what works pretty well. But now I want to add some more layers to an existing QGis Project. ...
2
votes
2answers
71 views

Can't transform lines to polygons

I have a similar question to: How to join lines in QGIS for later using "lines to poly"? I have a line shapefile that I wish to transform into a polygon shapefile. After making some ...
1
vote
1answer
28 views

How do you extract the data behind a raster histogram

Bit of a newbie, so this may be a daft question. I have an .ecw picture - it is has no CRS, as it is a picture taken at ground level with an NIR camera. It was originally converted from a RAW image. ...
1
vote
0answers
41 views

Geometric functions in field calculator in QGIS

I had a look in the manual of QGIS and I also browsed the Internet to find some useful information about the geometric functions of the field calculator. I've found this post but I'm still confused. ...
1
vote
1answer
29 views

Pattern Effect in Pie Charts in QGIS?

I have more than 3 attributes to add to pie charts in QGIS, so I need a patterned fill e.g.dots, lines. Using a grey scale gives white, black and grey but using different shades of grey doesn't work ...
1
vote
0answers
34 views

How can I get a .asc file to load into QGIS?

I got some files from an ag plane that are in ASCII format. I can not seem to be able to get them to load into QGIS without the This is a link to the file I am trying to use. ...
2
votes
0answers
25 views

infer the altitude from a DTM & finally provide it to point / evincere la altitudine da un DTM & finalmente fornirla a dei punti

I would like to complete a point vector's table with Z data. I am not able to take Z coordinate from a dtm (downloaded from ...
1
vote
0answers
32 views

Generating Heat Maps with GeoHash

I have a long list of GeoHash codes for a certain geographic region. I'm using 6-character precision so for example if the area under study was Earl's Court in London, I would have a few six letter ...
1
vote
1answer
30 views

How to programmatically create nested layer groups?

Using PyQGIS via the QGIS 2.4.0 Python console and the editor, I can create parallel groups for storing some layers with: MyFirstGroup = iface.legendInterface().addGroup('Group No. 1') MySecondGroup ...
2
votes
0answers
18 views

QGIS small install package for use in low-bandwidth settings?

I'm a cartographer and data analyst with experience using ArcGIS and QGIS to format data and produce maps for a global public health contract. I am working with a group of QGIS learners from Africa ...
4
votes
2answers
85 views

How to enter a date into the attribute table?

This may be something simple stupid but in QGIS 2.4 I have created a date column. How do I enter the date in correctly. Every time I type a date in, in whatever format it does not move that entered ...
3
votes
1answer
58 views

Drawing isochrones on map?

I am a fourth year graduation student of the Amsterdam University of Applied Sciences. I am currently working on my final thesis for which I am doing research on the Amsterdam Airport catchment area. ...
14
votes
3answers
256 views

Zigzag Line Symbol in QGIS

I'm looking for a zigzag line symbol in QGIS. Is there perhaps an easy way to do this that I'm missing? I have tried creating a marker line using a simple triangle marker (^) and adjusting the size of ...
2
votes
1answer
88 views

How to measure distance between points based on elevation?

I need to be able to measure distances between points, however the distance need to be calculated in relations to elevation. The points are homes of storytellers from the 19th century and the places ...
1
vote
1answer
48 views

How to create a Processing script using the shortest path algorithm?

I'm currently using the Road Graph plugin to find the shortest path in a road network - however, I'd like to put this to a processing script (to be used in a model later) and the Road Graph Plugin has ...
0
votes
0answers
15 views

How to mosaic lots of TIF files [duplicate]

I have 550 piece of .Tif fil files. I need to mosaic them. I tried QGIS, ERDAS and ArcGIS but they crashed everytime. In Erdas Tif's stored only 4GB limit of size. Which solution can be useful for me ...
2
votes
1answer
39 views

Opening GeoTIFF (georeferenced in ArcGIS for Desktop) in QGIS?

I tried to open a georeferenced geotiff created in ArcGIS for Desktop in QGIS. I could open them but they are not in the right spots. These raster datasets contains .aux .rrd .tfwx .tif.aux.xml ...
0
votes
0answers
16 views

Is there a way to include code/language for offsets within the “script” at the CRS dialogue screen

I'm pretty new to QGIS and coming from being just good enough to be dangerous in Manifold GIS. I have some JPEG 2000 rasters that were exported from Manifold in UTM 18S, and then imported into QGIS, ...
2
votes
0answers
41 views

QGIS 2.4 NVIZ Solution

I am going to ask this question better: What happened with NVIZ? I do not know the exact version that nviz stopped working but it seems around version 2 of QGIS. There are two ways to get to nviz in ...
1
vote
1answer
68 views

SQLite instead of gdb

I use ArcGIS and Qgis and I want to have common protocol and format of my files. To use a separate file for each program is not the best way, I don’t want to make a mess of data. I would ask if SQLite ...
1
vote
1answer
26 views

Unable to add features in QGIS 2.4.0

QGIS beginner problem. I can no longer create features with "Add Feature" in QGIS. The info triangle message is "Transform error caught: forward transform of (0.000000, 0.000000) PROJ.4: ...
2
votes
0answers
44 views

How to get user and password of a PostGIS layer

I wonder if it is possible to get the user and password for a PostGIS database if they are stored in the PostGis connection information. I get the connection information at the moment from the ...
2
votes
2answers
35 views

QGIS layer tree API returns only groups and not layers

I am trying to use the QGIS python API to read out the groups and layers in a QGIS (2.4) project. Here is a code snippet from my script, which is run from a shell, not from the QGIS python console! ...